Target camera will always look at the center of Target location parameter. So you can set Cursor where you want camera always look at and then click Look at Cursor so it'll show you in blender where camera will look at in the engine. It's the only Simple way to target camera at special point.

Another way is to create a simple logic node sutup with camera move node, but here you can always target camera at specific object. I prepeared for you an example.look_at_setup.blend